1. Field of the Invention
The present invention relates to the handling of sheet material and, more particularly, is directed to an integral ream collection table and transfer conveyor assembly for use with a continuous discharge sheeting machine.
2. The Prior Art
Sheeting machines are known in which cut sheets, particularly of paper, are advanced seriatim along a delivery conveyor system to a collector device where the sheets collect into piles. Typical collector units enable sheets to collect on a reciprocating platform which descends at the growing rate of the stack. In the case of sheet ream collection, after a predetermined pile has accumulated on the lift platform, the platform is lowered down to a level beneath a transfer belt conveyor system on which the ream pile is deposited. The transfer conveyor then transports the ream pile to a packaging or cartoning station.
Ream transfer conveyor systems are known which contain a transversely directed slat conveyor portion for conducting the ream pile off in a direction orthogonal to the initial transport flow path of the ream pile from the collector. In order to facilitate transfer of the ream pile from the initial laterally directed transfer conveyor portion onto the slat conveyor, the slat chain is initially tilted toward the lateral transfer conveyor portion in order to allow the ream to slide over it without catching on the adjacent side edge of the slats. After the ream has been deposited on the slat conveyor, the slats are leveled and raised relative to the slat conveyor top surface so as to conduct the ream in the orthogonal direction. One known arrangement for moving the slats of a slat conveyor between the slanted, receiving position and the upraised, leveled transport condition utilizes a pneumatically powered cam shaft device having corresponding cam surfaces for selectively engaging beneath the upper portion of the slat chain. One drawback with this arrangement, however, is that the positioning mechanism necessitates the use of heavy and expensive hardware, which is cumbersome and leads to high construction costs.
The present invention provides for a simplified and less expensive positioning mechanism for use with an orthogonally directed slat conveyor and, furthermore, concerns a ream lift table having criss-crossed, collapsible scissors arms and a constant speed drive arranged to vary the rate of descent of the lift table during ream collection operation.